The Evolution of Iron
1997; Wiley; Volume: 160; Issue: 2 Linguagem: Inglês
10.1002/1521-396x(199704)160
ISSN1521-396X
Autores Tópico(s)Metallurgical Processes and Thermodynamics
ResumoElectrolytic iron is the important mother material for the fundamental research of iron and its alloys. Recently, the purification of electrolytic iron from a purity of 99.9 to 99.998 mass% has been achieved. Properties such as ductility, strength, and recrystallization temperature of the high-purity material are quite different from the accepted values of conventional electrolytic iron. The ductility of high-purity iron and its alloys is strongly affected by trace impurities such as carbon, nitrogen, sulfur, phosphorus, etc. It is found that phosphorus improves remarkably the ductility of iron above 773 K, although it causes intergranular fracture at low temperatures. On the other hand, 5 mass ppm of sulfur in iron suffices to reduce strongly the hot ductility of iron between 673 and 1173 K. It is concluded that the limit of soluble sulfur in iron with excellent hot ductility is less than 1 mass ppm. The ductility of Fe–50 mass% Cr alloy between room temperature and 1573 K is improved by the purification. The reduction of the nitrogen content suppresses the formation of σ phase in the Fe–50 mass% Cr alloy.
Referência(s)